The Internet provides access to a wide variety of resources. For example, video and/or audio files, as well as web pages for particular subjects or particular news articles, are accessible over the Internet. Access to these resources presents opportunities for content (e.g., advertisements) to be provided with the resources. The pairing of content with requested resources can generate value. For example, a web page can include content slots in which advertisements or other content can be presented. These content slots can be defined in the web page or defined for presentation with a web page, for example, in a pop-up window.